in reply to SQLite3 use in production
Another good use for SQLite, which is where I use it, is in redistributable and particularly end-user desktop applications. They're guaranteed to be single-user, and embedding MySQL would be more trouble than it's worth. SQLite requires no installation or configuration. Its only overhead is the DBD and supporting client libraries, but those are pretty light-weight. But for a server-side application that can accept multiple client connections, I don't see SQLite as offering much of an advantage.